Ship stabilizer fin

ABSTRACT

A light-weight, strong, low cost fin for ship stabilization. The fin is composed of plastics materials, such as polystyrene, polyurethane, and the like. The fin is strong and durable in its use as a ship stabilizer. However, the type of materials used in the fin permit the fin to be readily crushed or broken upon impact with other objects, to prevent transmission of forces to the ship which might damage the ship which is stabilized by the fin.

United States Patent 1191 Larsh June 25, 1974 SHIP STABILIZER FIN Primary ExaminerTrygve M. Blix E [76] Inventor r is f i z Rldge Assistant Exammer-Charles E. Frankfort Attorney, Agent, or FirmJacox & Meckstroth [22] Filed: Feb. 9, 1973 [21] AppljNo; 331,333 57 ABSTRACT I v A light-weight, strong, low cost fin for ship stabiliza- U-S. Cl tion The fin is omposed of plastics materials uch as [5 6 polystyrene polyurethane and the The is Fleld of ch 1 14/126, 135, 142, 15 strong and durable in its use as a ship stabilizer. l-low- 244/123 ever, the type of materials used in the fin permit the fin to .be readily crushed or broken upon impact with [56] References Clted other objects, to prevent transmission of forces to the UNITED STATES PATENTS ship which might damage the ship which is stabilized 2,773,792 12/1956 Nebesar 244/123 y the 3,377,975 4/1968 Field 3,687,100 8/1972 Larsh 114/126 4 Clam, 8 Drawmg Flgures.

PATENTEBJUNZSIQH sum 2 or 2 Av -Fa SI-IIP STABILIZER FIN BACKGROUND OF THE INVENTION In the'past various types and styles of stabilizers for ships have been employed. So far as is known, all of such stabilizers have been of rigid, sturdy, expensive construction. However, the cost of such stabilizers is high. Furthermore, a stabilizer fin frequently comes into engagement with another object such as a pier, dock, or other underwater object. In the past, such engagement of the fin with such an element has resulted in damage to the ship which is stabilized by the fin, because such engagement of the fin with a pier, dock, or other underwater object has resulted in transmission of considerable forces to a shaft which supports the fin and/or to the ship which is stabilized by the fin.

An object of this invention is to provide a ship stabilizer fin which can be produced at low costs, which is light in weight, is crushable upon impact, for protection of the ship, and which is easily and readily replaceable.

Another object of this invention is to provide such a stabilizer fin which is capable of balancing hydraulic forces 'which are applied thereto during operation thereof. i

Another object of this invention is to provide such a stabilizer fin which produces negligible water turbulence when there is relative movement between the fin and the water.

Other objects and advantages of this invention reside in the construction of parts, the combination thereof,

the method of manufacture, and the mode of operation, as will become more apparent from the following description.

FIG. 1 is a perspective view illustrating fin members of this invention in association with a ship for stabilization thereof. 1

FIG. 2 is a perspective view, drawn on a larger scale than FIG. 1, showing a tin of this invention.

FIG. 3 is an exploded perspective view, drawn on a larger scale than FIG. 2, illustrating a method of producing a fi'n of this invention.

FIG. 4 is a side elevational view, with parts broken away and shown in section, of a fin of this invention.

FIG. 5 isa perspective view, with parts broken away and shown in section, of a fin of this invention.

FIG. 6 is an enlarged sectional view taken substantially on line 6-6 of FIG. 5.

FIG. 7 is an enlarged sectional view taken substantially on line 74 of FIG. 6.

'FIG. 8 is a view taken-substantially one line 88 of FIG. 6.

DETAILED DESCRIPTION OF THE INVENTION v halves 30a and 30b, which are joined together in any between the mold halves 30a and 30b. The core 34 is generally rectangular as it appears in side elevation, but has a generally rectangular opening 36 at the central portion thereof. The core 34 is tapered in thickness from the upper edge thereof to the lower edge thereof. and is tapered in thickness from the central opening 36 to the ends thereof, as shown in FIG. 3. The core 34 has openings 38 therethrough', as shovm in FIG. 3.

Each of the mold halves 30a and 30b has a longitudinal internal groove 40. Each of the mold halves 30a and 30b has an inwardly turned flange 44 along the bottom edge thereof and along each end thereof for engagement between the mold halves 30a and 30b. Each mold half has a ledge 50 centrally located at the upper edge thereof. Studs 52 extend upwardly from each ledge 50. The core 34 is positioned between the mold halves 30a and 30b, and any suitable means, not shown, is employed to maintain the core 34 centrally located between the mold halves 3011 and 30b and spaced from the sides, ends and bottom thereof.

Then a pair of angular connector members 60 are positioned so that a leg 62 thereof rests upon one of the ledges 50 and another leg 64 thereof hangs downwardly into the central opening 36 of the core 34. Each of the legs 62 has openings 66 therein and studs 52 extend through at least two of the openings 66 to retain the connector members 60 in position. The leg 64 of each connector member 60 has openings 68 therethrough.

Then with the core 34 and the connector members 60 so positioned, a suitable material 70, preferably of the plastics type, such as expandable polyurethane or the like is introduced in a liquid state into the cavity formed by the mold halves 30a and 30b. The plastics material 70 is sufficient in quantity to fill the mold cav-. ity and to occupy all space therein which is not occupied by the core 34 and the legs 64 of the connector members 60. The plastics material 70 flows completely around and encompasses the core 34. The plastics material 70 flows through the openings 38 in the core 34, and through the openings 68 in the legs 64 of the connector members 60. The plastics material 70 also flows into the internal grooves 40 of the mold members 30a and 30b.

The plastics material 70 is then permitted to solidify and a fin 18 results. The mold members 30a and 30b and the fin 18 are then separated. The fin 18 then has an appearance as illustrated in FIGS. 2, 5, 6, 7 and 8. Flow of the plastics material 70 into the grooves 40 provides ribs 76 on the surfaces of the fin l8, and ribs 78 are also formed at the lower edge of the fin 18 as shown in FIGS. 5 and 6. The leg 62 0f each connector member 60 is bolted onto a suitable connection member 79 of one of the shafts 20, as shown in FIGS. 1 and Thus, the ship 22 is provided with stabilizer fins 18 which are strong, but light in weight. The ribs 76 and 78 aid in producing smooth flow of water over and along the fins as the ship 22 moves. Because of the tapered shape of each fin 18, hydraulic forces applied thereto are balanced during operation thereof, and minimum water flow turbulence is created during operation of the tin. The fins are employed to stabilize the ship 22 in amanner such as that described in US. Pat.

No. 3,687,100, owned by the inventor herein. If during 1 '3 movement of the ship 22, either of the fins,l8 should come into engagement with an object, such as an underwater object, rock, or pier or the like, the fin l8 easily and readily crushes or breaks, without transmitting objection forces to the shaft and to the ship 22. Thus, the fins 18 are expendable to protect the shaft 20 the ship 22 from damage. Due to the fact that a fin 18 can be produced at relatively low costs and may be easily mounted upon one of the shafts 20, the fin 18 is highly desirable over known stabilizer fins which are relatively expensive and which are rigid and which are capable of transmitting damaging forces to the ship when the fin engages an underwater object.

Due to the fact that the fin 18 is of plastics materials having a specific gravity less than water, if the entire fin or portions thereof are broken away from the connector member or from other portions of the fin, such broken away portions rise to the surface of the water and float. Thus, these portions may be easily recovered. Damage to a fin may be repaired in some situations.

' A stabilizer fin of this invention can be produced in various sizes and shapes and the dimension proportions between the core member and the connector member The invention having thus been described, the following is claimed:

l. A stabilizer fin for ships comprising an elongate one-piece core mernber of light-weight plastics material, the core member having a length dimension and a width dimension providing a pair of spaced-apart longitudinal edges and a pair of spaced-apart transverse edges, there being a notch extending from one longitudinal edge toward the other longitudinal edge and having a depth dimension less than that of a transverse edge dimension, the notch being substantially equidistant from the transverse edges, a rigid connector member having a body portion within the notch and a connection portion extending from the core member, a second plastics material encompassing the core member and covering the core member and filling the notch therein and securing the connector member to the core member.

2. The stabilizer fin of claim 1 in which the core member is polystyrene material and the second plastics material is polyurethane.

3. The stabilizer fin of claim 1 which includes two connector members, each of which has a body portion within the opening of the core member and a flange portion exterior of the core member.

4. The stabilizer fin of claim 1 in which the body portion of the connector member and the core member have apertures therethrough through which a part of the second plastics material extends for securing the connector member and the second plastics material to the core member. 

1. A stabilizer fin for ships comprising an elongate one-piece core member of light-weight plastics material, the core member having a length dimension and a width dimension providing a pair of spaced-apart longitudinal edges and a pair of spaced-apart transverse edges, there being a notch extending from one longitudinal edge toward the other longitudinal edge and having a depth dimension less than that of a transverse edge dimension, the notch being substantially equidistant from the transverse edges, a rigid connector member having a body portion within the notch and a connection portion extending from the core member, a second plastics material encompassing the core member and covering the core member and filling the notch therein and securing the connector member to the core member.
 2. The stabilizer fin of claim 1 in which the core member is polystyrene material and the second plastics material is polyurethane.
 3. The stabilizer fin of claim 1 which includes two connector members, each of which has a body portion within the opening of the core member and a flange portion exterior of the core member.
 4. The stabilizer fin of claim 1 in which the body portion of the connector member and the core member have apertures therethrough through which a part of the second plastics material extends for securing the connector member and the second plastics material to the core member. 